1. Field of the Invention
The present invention relates to an apparatus for regulating flow through a passage. More particularly, the present invention relates to a rotary valve.
2. Description of Related Art
Spark ignition internal combustion engines often employ a butterfly valve in a throttle valve assembly to control air intake. While a butterfly valve works adequately, the horsepower can be increased if the valve employed in the throttle assembly is less restrictive, since the butterfly valve shaft and the plate remain in the airflow path, obstructing airflow while in open throttle. In the past, slide throttles, pivoting variable intakes and other means have been used to reduce restriction in the intake path. An important consideration in the design of non-butterfly intake valves is airflow control, turbulence and low throttle response. Because of their long use and development, butterfly intake valves have been developed which adequately address those issues, but many non-butterfly systems still present problems in partial throttle situations. One non-butterfly intake control type utilizes barrel valves which rotate between a closed position and an open position. However, known barrel valve systems have numerous limitations and disadvantages compared to butterfly systems at partial throttle openings. The present invention solves these and other problems previously encountered with barrel valve intake systems.